金仓麦麦
前情提要：初探 RWC 秘境 上回说到，金仓赵今麦在师父的指导下成功搭建了 KES RWC 三节点集群 。看着监控面板上跳动的数据流，她仿佛看到了数字世界的血脉在三个节点间奔涌不息。但师父的一席话让她陷入沉思："集群如同活物，需懂得呼吸吐纳之道。今日教你集群的'生长术'与'缩骨功'。"
回归现实。 金仓数据库 中默认配套了集群管理的图形化操作工具。但对于一些权限管控严格操作环境，或者操作系统以命令行模式启动，就只能使用指令对数据库集群进行管理和维护。
为了应对业务扩张和数据量增长，或者建设完善多机房、异地容灾机制，我们时常需要对数据库集群进行扩容。
Part 1. 集群生长的秘密仪式 神秘祭坛的召唤 赵今麦轻点终端，三节点的运行状态如星图般展开：
[kingbase@kes1 ~]$ repmgr cluster show ID | Name | Role | Status | Upstream | Location | Priority | Timeline | LSN_Lag | Connection string ----+-------+---------+-----------+----------+----------+----------+----------+---------+--------------------------------------------------------------------------------------------------------------------------------------------------------------- 1 | node1 | primary | * running | | default | 100 | 1 | | host=kes1 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 2 | node2 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes2 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 3 | node3 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes3 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 [kingbase@kes1 ~]$ repmgr service status ID | Name | Role | Status | Upstream | repmgrd | PID | Paused? | Upstream last seen ----+-------+---------+-----------+----------+---------+------+---------+-------------------- 1 | node1 | primary | * running | | running | 2970 | no | n/a 2 | node2 | standby | running | node1 | running | 2167 | no | 1 second(s) ago 3 | node3 | standby | running | node1 | running | 2163 | no | 0 second(s) ago [kingbase@kes1 ~]$ "就像给大树嫁接新枝，"师父的声音在耳边响起，"需先寻得灵土——准备同源而生的 kes4 服务器。"
血脉相连的仪式 配置免密通道时，赵今麦仿佛在节点间架设无形的桥梁：
[kingbase@kes1 zip]$ sudo ./trust_cluster.sh ... connect to "kes4" from current node by 'ssh' root:0 kingbase:0..... OK check ssh connection success! [kingbase@kes1 zip]$ 这让她想起武侠小说中的经脉贯通，节点间的信任通道就是集群的任督二脉。
生命复刻的魔法 透过魔法球，我们看到了新土壤的养分足以支撑新树移栽。
# 从 kes1 复制客户端工具和授权文件到 kes4 服务器 [kingbase@kes1 V009R004C010]$ pwd /opt/Kingbase/ES/V9/KESRealPro/V009R004C010 [kingbase@kes1 V009R004C010]$ scp -r ClientTools license.dat kes4:/opt/Kingbase/ES/V9/ ... # 修改配置文件 [kingbase@kes4 zip]$ diff install.conf install.conf.bak | grep '^<' < all_ip=(kes1 kes2 kes3 kes4) < net_device=(ens160 ens160 ens160 ens160) < net_device_ip=(192.168.43.91 192.168.43.92 192.168.43.93 192.168.43.94) < expand_type= "0" < primary_ip= "kes1" < expand_ip= "192.168.43.94" < node_id= "4" < sync_type= "0" < install_dir= "/home/kingbase/cluster/install" < zip_package= "/opt/Kingbase/ES/V9/ClientTools/guitools/DeployTools/zip/db.zip" < net_device=(ens160) < net_device_ip=(192.168.43.94) [kingbase@kes4 zip]$ 执行扩容时，屏幕闪烁的代码如同跳动的符文：
[kingbase@kes4 zip]$ pwd /opt/Kingbase/ES/V9/ClientTools/guitools/DeployTools/zip [kingbase@kes4 zip]$ ./cluster_install.sh expand [CONFIG_CHECK] will deploy the cluster of [RUNNING] success connect to the target "192.168.43.94" ..... OK [INSTALL] load config from cluster.....OK [CONFIG_CHECK] file format is correct ... OK [NOTICE] starting backup (using sys_basebackup)... [INFO] executing: /home/kingbase/cluster/install/kingbase/bin/sys_basebackup -l "repmgr base backup" -D /home/kingbase/cluster/install/kingbase/data -h kes1 -p 54321 -U esrep -c fast -X stream -S repmgr_slot_4 [NOTICE] standby clone (using sys_basebackup) complete [NOTICE] you can now start your Kingbase server [NOTICE] standby node "node4" (ID: 4) successfully registered [2025-03-07 23:56:01] [NOTICE] redirecting logging output to "/home/kingbase/cluster/install/kingbase/log/kbha.log" ID | Name | Role | Status | Upstream | Location | Priority | Timeline | LSN_Lag | Connection string ----+-------+---------+-----------+----------+----------+----------+----------+---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 1 | node1 | primary | * running | | default | 100 | 1 | | host=kes1 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 2 | node2 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes2 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 3 | node3 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes3 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 4 | node4 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=192.168.43.94 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 [kingbase@kes4 zip]$ 赵今麦屏息凝视，直到新节点如破茧之蝶般现身集群：
此刻的监控面板上，数据洪流自动分出一支注入新节点，宛如江河开凿新河道般自然。
Part 2. 缩容的精准手术 诊断病灶节点 当需要下线 node3 时，赵今麦先以"望闻问切"之法检查节点状态：
[kingbase@kes3 ~]$ repmgr node check Node “node3”: Server role: OK (node is standby) Replication lag: OK (0 seconds) WAL archiving: OK (0 pending archive ready files) Upstream connection: OK (node “node3” (ID: 3) is attached to expected upstream node “node1” (ID: 1)) Downstream servers: OK (this node has no downstream nodes) Replication slots: OK (node has no physical replication slots) Missing physical replication slots: OK (node has no missing physical replication slots) Configured data directory: OK (configured “data_directory” is “/home/kingbase/cluster/install/kingbase/data”) 确认节点健康后，她开始准备这场"无痛摘除术"。
精准切割术 修改配置文件如同调整手术方案，注意定位文件中 [shrink] 部分：
[kingbase@kes1 zip]$ diff install.conf install.conf.bak | grep '^<' < shrink_type= "0" < primary_ip= "kes1" < shrink_ip= "kes3" < node_id= "3" < install_dir= "/home/kingbase/cluster/install" [kingbase@kes1 zip]$ 执行缩容命令时，她仿佛看到数据流被优雅地重定向：
[kingbase@kes1 zip]$ ./cluster_install.sh shrink [CONFIG_CHECK] will deploy the cluster of [RUNNING] success connect to the target "kes3" ..... OK [RUNNING] The /home/kingbase/cluster/install/kingbase/bin dir exist on "kes3" ... OK ID | Name | Role | Status | Upstream | Location | Priority | Timeline | LSN_Lag | Connection string ----+-------+---------+-----------+----------+----------+----------+----------+---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 1 | node1 | primary | * running | | default | 100 | 1 | | host=kes1 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 2 | node2 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes2 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 3 | node3 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes3 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 4 | node4 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=192.168.43.94 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 [INFO] node:kes3 can be deleted ... OK [NOTICE] unregistering node 3 [INFO] standby unregistration complete 2025-03-08 00:06:44 DB on "[localhost]" stop success. ID | Name | Role | Status | Upstream | Location | Priority | Timeline | LSN_Lag | Connection string ----+-------+---------+-----------+----------+----------+----------+----------+---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 1 | node1 | primary | * running | | default | 100 | 1 | | host=kes1 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 2 | node2 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes2 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 4 | node4 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=192.168.43.94 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 [kingbase@kes1 zip]$ 整个过程如庖丁解牛，node3 平滑下线不留隐患。
术后康复观察 确认集群状态，四节点缩容成三节点后，已自动重组为新的稳定三角：
[kingbase@kes1 zip]$ repmgr cluster show ID | Name | Role | Status | Upstream | Location | Priority | Timeline | LSN_Lag | Connection string ----+-------+---------+-----------+----------+----------+----------+----------+---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 1 | node1 | primary | * running | | default | 100 | 1 | | host=kes1 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 2 | node2 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=kes2 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 4 | node4 | standby | running | node1 | default | 100 | 1 | 0 bytes | host=192.168.43.94 user=esrep dbname=esrep port=54321 connect_timeout=10 keepalives=1 keepalives_idle=2 keepalives_interval=2 keepalives_count=3 tcp_user_timeout=9000 [kingbase@kes1 zip]$
后记：集群生命周期的顿悟 "这是数字生命的呼吸，"师父缓缓道，"优秀的 DBA 不是操作工，而是把握集群生命韵律的医者。KES 的扩缩容不是简单的加减法，而是让系统始终保持'黄金平衡点'的艺术。"
月色下的机房，赵今麦凝视着呼吸灯有节奏的明灭。
她突然领悟到：
"扩缩容的真谛，在于让数据库学会像生物一样——在春天生长，在秋天沉淀。就像《庄子》所言：'其生若浮，其死若休'。每个节点的加入都为集群注入新活力，而优雅下线则是数字生命的轮回。"
但望着集群安装脚本，她又在思考：
"若能在 dry-run 中预见操作结果，就像拥有预见未来的水晶球，该多好？"
[kingbase@kes4 zip]$ ./cluster_install.sh help Do not choose any method, install/expand/shrink! 机房外，晨曦微露。
赵今麦知道，这场关于数据库生命奥秘的探索，才刚刚开始......
金仓数据库产品体验官招募 ING
🎁福利时间
关注本公众号，在本文留言 ，点赞数 最多的一位送出金仓定制台历一本。截止时间：3月12日17点。
Have a nice day ~ ☕
🌻 往期精彩 ▼
-- / END / --
👉 这里可以找到我
👉 这里有得聊
如果对国产基础软件（操作系统、数据库、中间件）感兴趣，可以加群一起聊聊。 关注微信公众号：少安事务所，后台回复[群]，即可看到入口。
如果这篇文章为你带来了灵感或启发，请帮忙『 三连 』吧，感谢！ღ( ´･ᴗ･` )~
